Of the tiles that are used as wall, floor or ceiling covering in public places such as subway stations, tunnels, theme parks, etc., it is expected that they are strong, durable, easily washable, easy maintainable, and are vandalism resistant. For specific applications such as hospitals, it is required that the tiles that are used for wall, floor-, or ceiling covering moreover are chemically inert. For other applications such as wall covering in meeting rooms of office buildings it can be desirable that the tiles have certain magnetic properties so that the wall can be used as a magnetic plate.
Ceramic tiles have some of the above characteristics and the use of such ceramic tiles for wall, floor or ceiling covering is therefore known. The brochure “A Guide to Ceramic Tile Digital Decoration” by XAAR, published on 2 Sep. 2014, mentions on page 13 that such ceramic tiles can be printed with images to achieve certain decorative effects. By using ink-jet printing images can be applied to flat, ceramic tiles so as to for example mimic marble or natural stone. Furthermore the brochure by XAAR mentions on page 33 that texture can be applied to the surface of ceramic tiles through press processing. Texture in the surface of ceramic tiles makes the colored patterns or images that are printed on the tiles even more realistic. Traditional, non-digital pressing is an expensive process. XAAR predicts in its brochure of the 2 Sep. 2014 that traditional presses will be replaced in the future by a digital press process that can be set up faster and more cost efficiently.
In situations where tiles have to mimic certain materials such as marble, wood, etc., the smooth and glossy surfaces of ceramic tiles do not provide a sufficiently realistic impression so that the emotion of such materials, such as the warmth of wood, are not or not perfectly evoked. Texture application through non-digital or digital presses such as suggested by XAAR brings improvement, but pressing remains an expensive and complex process.
There are alternative techniques to apply bas-relief or texture to the surface of tiles. As mentioned by the American patent application US2014/0290511A1 titled “Methods of Producing Articles Having Three-Dimensional Topography” in section [0002] which uses laser technology to remove material from a surface by which the surface gets texture. Paragraph [0003] of the same American patent application reports that use can be made of an injection-molding technique with molds which provide bas-relief or texture to the surface. Another alternative is a stamp technique to modify the surface so as to apply structure and thus bas-relief to the surface (see paragraph [0004] of US2014/0290511A1). According to paragraph [0005] of US2014/0290511A1 one can deposit polymer material on a surface which also results in texture. However, all these known techniques are expensive and complex, as is also mentioned by US2014/0290511A1 in paragraph [0006]. US2014/0290511A1 claims to have found a lower-cost technique for applying texture to a surface in the application of ceramic powder through a screen process. Even if this screen process with ceramic powder is cheaper than the known techniques, increasing realism and emotion emanating from a color pattern or color image has not become any easier. After all, a two-dimensional color image needs according to US2014/0290511A1, paragraph [0011] to be printed on the texturized surface and printing on a non-planar surface is anything but easy.
Ceramic tiles also do not have a number of the above desired properties. For example, ceramic tiles have no magnetic properties and their strength is limited which means they can still crack, crumble, etc. in the case of vandalism or strong vibrations.
The European patent application EP2019267A2 titled “Aussenverkleidung einer Heizvorrichtung” describes a tile used in decorative interior applications such as covering of fireplaces or furnaces. The tile from EP 2019267A2 consists of a metal sheet that is being printed with a picture. On top of the image a transparent enamel layer is applied which may be suited to the image and bas-relief or texture applied to the surface of the tile. The tile from EP2019267A2 has as disadvantage that an image has to be printed on metal and that texture consists of gloss enamel making it again difficult to display highly realistic images such as a wood grain pattern and to evoke the associated emotions.
Outside the field of the present invention it is known from European patent application EP2213213A1 to apply a transparent anti-slip layer onto a sanitary surface, for example bottom surface of a bathtub, through a screen printing process. The anti-slip layer does not enhance the realism and the emotion of a two-dimensional image that was printed onto the sanitary surface. On the contrary, the anti-slip layer consists of its own pattern and therefore forms a second image that is applied over the printed image so that the image is partially hidden and/or at least blurred.
Furthermore, the international patent application WO2012/075548 titled “Heating Element” describes a heating element (11 in FIG. 3) which can be embedded into a vertical wall or a ceiling. The heating element from WO2012/075548 has better decorative properties and consists of a steel plate (13 in FIG. 3), a first enamel base layer (14 in FIG. 3), a second enamel top layer (14a in FIG. 3), and a printed image (14b in FIG. 3). The enamel top layer (14a) and the printed image (14b) receive a thermal treatment above 600° C.
In yet another domain, the British patent application GB726,198 suggests to give an alert plate, for example a license plate of a vehicle, better reflection properties by scattering glass beads by means of a laser over an enameled metal plate. Although the glass beads give a rougher texture to the surface of the enameled metal plate, they do not improve the realism and emotion of a two-dimensional image printed beneath.
In the domain of the alert plates the American patent U.S. Pat. No. 1,852,759 further describes a technique for making an enamel alert plate with two colors. On a metal plate (16 in FIG. 1), an enamel base layer (10 in FIG. 1) is applied. On top of that, an enamel coating (14 in FIG. 1) is applied. Finally, a final coating (16 in FIG. 1) is applied in a different color from the enamel coating (14 in FIG. 1). By means of a stencil (18 in FIG. 1) with openings (20 in FIG. 1) and a brush technique applied at the position of the openings (20 in FIG. 1) parts of the final coating (22 in FIG. 1) are then removed so that the color of the enamel coating (14 in FIG. 1) is there made visible. In this way, alert plates with 2 colors could be acquired in 1930.